Exhaust Questions

I just have 2 quick questions, and figured I'd get the thoughts of others on the boards.
I recently swapped out my stock midpipes for off road pipes, and it took roughly 6 days for my car to throw the expected "Check Engine" light. Is that normal that it would take that long for it to come on? Should have the delay checked out?
When deciding to go to off road pipes I always factored in the noise I should expect, but never the smell. After putting on the off road pipes my exhaust started smelling raw. Almost like a car from the 60s or 70s. I would assume this is normal with the 6 cats (3 on each side) now missing, but just wanted to mention it on the board and get thoughts.

Thanks Guys.